The XDrawText16 function is similar
to XDrawText except that it uses 2-byte or 16-bit characters. Both functions
allow complex spacing and font shifts between counted strings.

Each text
item is processed in turn. A font member other than None in an item causes
the font to be stored in the GC and used for subsequent text. A text element
delta specifies an additional change in the position along the x axis before
the string is drawn. The delta is always added to the character origin
and is not dependent on any characteristics of the font. Each character
image, as defined by the font in the GC, is treated as an additional mask
for a fill operation on the drawable. The drawable is modified only where
the font character has a bit set to 1. If a text item generates a BadFont
error, the previous text items may have been drawn.

For fonts defined
with linear indexing rather than 2-byte matrix indexing, each XChar2b
structure is interpreted as a 16-bit number with byte1 as the most significant
byte.

Both functions use these GC components: function, plane-mask, fill-style,
font, subwindow-mode, clip-x-origin, clip-y-origin, and clip-mask. They also
use these GC mode-dependent components: foreground, background, tile, stipple,
tile-stipple-x-origin, and tile-stipple-y-origin.

If the font member is not None, the font is changed before printing
and also is stored in the GC. If an error was generated during text drawing,
the previous items may have been drawn. The baseline of the characters are
drawn starting at the x and y coordinates that you pass in the text drawing
functions.

For example, consider the background rectangle drawn by XDrawImageString.
If you want the upper-left corner of the background rectangle to be at
pixel coordinate (x,y), pass the (x,y + ascent) as the baseline origin
coordinates to the text functions. The ascent is the font ascent, as given
in the XFontStruct structure. If you want the lower-left corner of the
background rectangle to be at pixel coordinate (x,y), pass the (x,y - descent
+ 1) as the baseline origin coordinates to the text functions. The descent
is the font descent, as given in the XFontStruct structure.